/*
* Copyright (c) 2021 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#if (DEVELOPMENT || DEBUG) && !KASAN
#include <sys/sysctl.h>
#include <libkern/stack_protector.h>
__attribute__((noinline))
static int
check_for_cookie(size_t len)
{
long buf[4];
long *search = (long *)(void *)&buf[0];
size_t n;
assert(len < sizeof(buf));
assert(__stack_chk_guard != 0);
assert(((uintptr_t)search & (sizeof(long) - 1)) == 0);
/* force compiler to insert stack cookie check: */
memset_s(buf, len, 0, len);
/* 32 x sizeof(long) should be plenty to find the cookie: */
for (n = 0; n < 32; ++n) {
if (*(search++) == __stack_chk_guard) {
return 0;
}
}
return ESRCH;
}
static int
sysctl_run_stack_chk_tests SYSCTL_HANDLER_ARGS
{
#pragma unused(arg1, arg2, oidp)
unsigned int dummy = 0;
int error, changed = 0, kr;
error = sysctl_io_number(req, 0, sizeof(dummy), &dummy, &changed);
if (error || !changed) {
return error;
}
kr = check_for_cookie(3);
return kr;
}
SYSCTL_PROC(_kern, OID_AUTO, run_stack_chk_tests,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED | CTLFLAG_MASKED,
0, 0, sysctl_run_stack_chk_tests, "I", "");
#endif /* (DEVELOPMENT || DEBUG) && !KASAN */